Determination of the order parameter of CuPt-Bordered GaInP2 films by x-ray diffraction

We present quantitative characterization of atomic ordering in semiconductor alloy films by x-ray diffractometry. In particular, we show that the order parameter of CuPt-B ordered GaInP2 films can be determined without measuring the fundamental reflections or examining structural details of the ordered domains. Our method is based on the fact that the ordering peak is modulated by statistical displacements of atom planes, which is a function of the degree of ordering. Therefore, by comparing two or more ordering peaks in an x-ray spectrum, the order parameter of an ordered film can be extracted solely for those regions that are, in fact, ordered. The method can straightforwardly be extended to other ordered alloys.